3.8 userland build fails on amd64 and sparc64

[Dag Richards]

After extracting sources from the cd,  checking out current, building 
installing and booting from the new kernel, make build fails.

The error message indicates that xargs is being called with an 
unsupported argument, "-r" as I recall.  If I then just build and 
install xargs the make build completes.

This has happened now on both a sparc64 and an amd64 machine.